What's with all the drooping aileron questions lately?
A320 series ailerons and elevators droop because pressure is not retained in the servos when hydraulics are off. There is nothing special about fly by wire that would cause it, other than the lack of cables.
Rudders on all large aircraft will displace in a strong wind. Large aircraft don't have gust locks on the rudder (not even the Dash-8), they have dampers, that protect the rudder from being slammed over.
Incidently, the newest A320 series ailerons don't droop. Not sure what's different about them, I'll see what I can find out.
The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.